bpf: Explicitly check accesses to bpf_sock_addr

{
  "id": "93114348636b36d448ed502ce1c3538197f188a25b5f9534b6f892f10f48c35c",
  "url": "https://osv.dev/vulnerability/CVE-2025-40078",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "bpf: Explicitly check accesses to bpf_sock_addr",
    "summary": "In the Linux kernel, the following vulnerability has been resolved: bpf: Explicitly check accesses to bpf_sock_addr Syzkaller found a kernel warning on the following sock_addr program: 0: r0 = 0 1: r2 = *(u32 *)(r1 +60) 2: exit which triggers: verifier bug: error during ctx access conversion (0) This is happening because offset 60 in bpf_sock_addr corresponds to an implicit padding of 4 bytes, right after msg_src_ip4. Access to this padding isn't rejected in sock_addr_is_valid_access and it thus later fails to convert the access. This patch fixes it by explicitly checking the various fields of bpf_sock_addr in sock_addr_is_valid_access. I checked the other ctx structures and is_valid_access functions and didn't find any other similar cases. Other cases of (properly handled) padding are covered in new tests in a subsequent patch.",
    "evidence": "osv:CVE-2025-40078",
    "products": [
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    "severity": "unknown",
    "structured": {
      "id": "CVE-2025-40078",
      "aliases": [
        "CVE-2025-40078"
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      ],
      "modified": "2026-10-28T02:30:26.076285648Z",
      "provider": "osv",
      "references": [
        "https://cert-portal.siemens.com/productcert/html/ssa-019113.html",
        "https://cert-portal.siemens.com/productcert/html/ssa-457936.html",
        "https://git.kernel.org/stable/c/4f00858cd9bbbdf67159e28b85a8ca9e77c83622",
        "https://git.kernel.org/stable/c/6d8b1a21fd5c34622b0c3893c61e4a38d8ba53ec",
        "https://git.kernel.org/stable/c/6fabca2fc94d33cdf7ec102058983b086293395f",
        "https://git.kernel.org/stable/c/76e04bbb4296fb6eac084dbfc27e02ccc744db3e",
        "https://git.kernel.org/stable/c/ad8b4fe5617e3c85fc23267f02500c4f3bf0ff69",
        "https://git.kernel.org/stable/c/cdeafacb4f9ff261a96baef519e29480fd7b1019",
        "https://git.kernel.org/stable/c/de44cdc50d2dce8718cb57deddf9cf1be9a7759f",
        "https://git.kernel.org/stable/c/fe9d33f0470350558cb08cecb54cf2267b3a45d2",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/40xxx/CVE-2025-40078.json",
        "https://nvd.nist.gov/vuln/detail/CVE-2025-40078",
        "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"
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      "provider_metadata": {
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        "evidence": "/id"
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    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 492644,
  "published_at": "2025-10-28T11:48:43.548+00:00"
}